まあ、放置状態だったのは事実だから一応。
<script type="text/javascript">
var T; onload = function () { T = new Date; };
</script>
<ul>
<li>
<a href="#" onclick="
var t = (new Date) - T;
var u = /^(([^:/?#]+):)?(\/\/([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?/.exec (this);
var q = location.search;
var r = /(time=)(\d+)/;
if (r.test (q)) { t += parseInt (q.match (r)[2]); q = q.replace (r, '$1' + t); }
else q = (u[6] ? u[6] + '\u0026' : '?') + 'time=' + t;
location.href = u[1] + u[3] + u[5] + q;
return false;
">次へ</a>
</li>
<li>
<a href="#" onclick="
var q = location.search;
var r = /(time=)(\d+)/;
var t = (r.test (q)) ? parseInt (q.match (r)[2]) : 0;
alert (t + 'ms. (' + Math.round (t / 1000) + ' 秒)');
return false;
">ここまでの経過時間</a>
</li>
</ul>
マルチポスト状態に何らかの対処をしてくれることを切に願う。